Up All Night to Urinate? Sleep Apnea May Be the Cause

Sleep apnea can be one reason you keep waking up at night to urinate. Waking to urinate, called nocturia, is a common symptom in people with sleep apnea¹. Small studies found that treating sleep apnea with CPAP reduced nighttime bathroom trips and the amount of urine made overnight for some people¹².

What is nocturia?

Nocturia means waking from sleep one or more times to urinate¹. Many people think it is just part of getting older or a bladder or prostate problem, and sometimes it is. But nocturia has many possible causes, including health conditions, medicines, alcohol and daily habits¹. Sleep apnea is one cause that is often missed.

A related term is nocturnal polyuria, which means the body makes too much urine at night³. This is different from having a small or overactive bladder.

How can sleep apnea make you urinate at night?

Obstructive sleep apnea (OSA) is a condition in which the throat closes off again and again during sleep. This causes pauses in breathing. These events put stress on the body.

Experts are still working out exactly how OSA leads to nocturia. The reasons are complex and not fully understood¹. A 2024 review explained that OSA¹:

• Affects the nervous system — the part that controls automatic body functions
• Increases oxidative stress — a type of cell wear and tear
• Can harm blood vessels — it can damage the lining of blood vessels

A long-held theory says that breathing pauses send a false "too much fluid" signal from the heart. This tells the kidneys to release more salt and water. The review noted that this theory has limits and does not explain everything¹.

Does CPAP reduce nighttime urination?

CPAP (continuous positive airway pressure) is a bedside machine that sends gentle air through a mask. It keeps the airway open during sleep. It is the most common treatment for OSA.

A 2015 review pooled five studies with 307 people who had both OSA and nocturia². It compared nighttime urination before and after CPAP. After treatment, people had²:

• Fewer bathroom trips — fewer nighttime trips to the bathroom
• Less urine — less urine made overnight
• Less sleepiness — less daytime sleepiness
• Fewer breathing pauses — far fewer, measured by the apnea-hypopnea index (AHI), the number of breathing pauses or shallow breaths per hour of sleep

The authors concluded that CPAP may be an effective treatment for nocturia linked to OSA².

What about stroke survivors?

Nocturia is very common in stroke survivors who have OSA³. One study enrolled stroke survivors with OSA in a rehabilitation unit³. About 69% made too much urine at night, and 69% woke more than once a night to urinate³.

People who could use CPAP were compared with people who could not or chose not to. After two weeks, the CPAP group made less urine at night, while the comparison group did not improve³. However, the number of nighttime bathroom trips did not change significantly³. Two weeks is short, and the groups were not randomly assigned. So it is hard to know what longer treatment might do.

How strong is the evidence?

The evidence is encouraging but limited. Most studies were small. They compared people before and after treatment rather than using randomized control groups²³. So the benefit is likely but not certain. CPAP can reduce nocturia in some patients, but not everyone¹.

Experts recommend looking at the whole picture, including other health conditions, medicines, alcohol and lifestyle¹. Besides CPAP, oral appliances and surgery for airway blockage could help some patients¹. The review also encouraged urologists to keep sleep apnea in mind. It asked them to refer patients for testing at a sleep center when it is suspected¹.

When should you get checked?

Ask your doctor about a sleep evaluation if you wake up at night to urinate and you also:

• Snoring or gasping — Snore loudly, or someone has seen you stop breathing or gasp during sleep
• Daytime tiredness — Feel tired or sleepy during the day
• Heart or stroke — Have high blood pressure, heart disease or have had a stroke
• No clear answer yet — Have already had bladder or prostate causes checked without a clear answer

A sleep study can show whether sleep apnea is part of the problem.

How Universal Sleep Solutions can help

At Universal Sleep Solutions, we offer in-lab and home sleep testing, CPAP and BiPAP setup and follow-up, oral appliance referral and Inspire evaluation for adults, as well as pediatric sleep care.

Contact Universal Sleep Solutions to schedule an evaluation.